On an aircraft, such as a rotorcraft, mechanical stops may be used to prevent blades from contacting one or more objects. For example, mechanical stops may impose a limit such that rotor blades may be precluded from hitting the body or frame of a helicopter.
The rotor information, or state, used by a helicopter diagnostic or flight control system can be measured in real-time and used to augment vehicle flight dynamics, improve disturbance rejection, detect damage, and limit rotor loads. This rotor information can include parameters such as flapping, pitching, and lead-lag accelerations, velocities, positions, and moments. Rotor states are not directly used in current helicopter flight control systems because the harsh rotor operating environment (centrifugal force, rain, dirt, sand, sunlight, vibrations, EMI, etc.), the difficulty providing reliable power and data to and from rotor sensors and the difficulty with fuselage dynamics contaminate sensed rotor state information.